Saturday, October 26, 2013

Per Eli's post below, Judith Curry's put up a silly guest post by Rud Istvan saying that climate change poses no water supply problems to Caribbean islands. There are too many fish to shoot as Istvan gishgallops them in the barrel, so let's talk first about where he's right: if nobody lived on these islands, then there'd be no water supply problems on those islands for those people who don't live there. In fact, a few people could live on those islands and if they always used far less water than the islands provided with a comfortable margin to spare, then again the problems from climate change would likely be minimal. His lamentation that humans are flawed is correct, while his claim that it doesn't count when climate change makes existing problems worse, not so much.

A brief aside: I've heard a similar claim from far more credible people that climate change's effects on biodiversity is overemphasized because it only adds to other stresses, most notably habitat destruction that keeps species from being able to migrate to new areas. I'm not buying it.

So the main issue is Istvan's claim that if you can draw a line of any length on the earth's surface from A to B without going below sea level and where A is high up, then B cannot have a saltwater intrusion problem. He only references Caribbean islands, but I don't see why the argument doesn't apply everywhere. So his first example was Pico Duarte in the Dominican Republic, at over 3000m elevation:

Pico Duarte's also over 100 km from Santo Domingo, and still further away from many other DR cities. Some of the other peaks he mentions are closer to those island's biggest cities, except for Pico Turquina in Cuba, which is closer to Port-au-Prince in Haiti than to Havana. Moving water a significant distance isn't easy, and contra Istvan, it's made harder when the landscape is mountainous.

Examining his claim, you would think California with a top elevation of 4400m wouldn't have a problem with saltwater intrusion, but we do. Los Angeles has been battling saltwater intrusion since 1915, and now spends millions of dollars injecting freshwater and treated wastewater to keep saltwater out. LA, btw, has significant mountains in the same county over 3000m tall, and still has the problem. LA probably has an advantage over many Caribbean islands in that its complex geology limits where saltwater can intrude.

Freshwater tends to float on top of salt water, which is good when you've got saltwater intrusion deep below ground but problematic if you live at sea level near the coast when sea level is rising. Coastal cities on continents tend to have saltwater oceans in one direction and freshwater-providing land in the other three. On islands that starts to get problematic, especially the smaller islands. Most contamination also occurs in the upper ground, so drawing from your uppermost freshwater because that's all you got raises another set of issues.

Finally, higher temperatures will mean greater water demand, for farming, landscaping, and for native vegetation that limit how much water gets past their roots and into the water table. My water district sees large changes in water demand depending on whether we have a warm or cool summer. In the next few years we plan to calculate how climate change is going to increase future demand, but it's safe to say that Caribbean islands will need more water for human activities while getting less of it in the water table.

So all that's pretty silly, but the most striking part for me is Rud Istvan's assertion that human mistakes harming the Caribbean societies count when they're committed by the people there, but not when they're committed by Rud Istvan and others who don't want to face the reality of climate change.

UPDATE: my attempt to comment at Curry's got bounced back. I'll store the comment here for now, pretty much the same as above:

As a director of the Santa Clara Valley Water District in northern California, I would like to inform Rud Istvan that the existence of mountains in a general area does not prevent saltwater intrusion. In Los Angeles, for example, the 3000m San Gabriel Mountains are physically adjacent to the city in the same county, and still they have to spend millions of dollars annually fighting saltwater intrusion. Contrast that to Cuba's highest peak, which is closer to Port-au-Prince Haiti than it is to Havana.

It's also important to note that warmer temperatures increase water demand from both artificial and natural landscapes, which will further depress freshwater tables and increase saltwater intrusion.

Istvan might consider doing further research on these issues before he reaches for what appears to be simplistic conclusions. Climate change makes water supply problems worse as a general matter. Islanders (and for what it's worth, everyone else) may not have handled their other water supply issues perfectly, but that's no excuse to keep greenhouse gas emissions high.

22 comments:

So, mere presence of mountains in a region doesn't mean no saltwater intrusion?

No, really?

"Istvan might consider doing further research on these issues before he reaches for what appears to be simplistic conclusions."

Not simplistic. Idiotic.

And quite frankly, he's not the only one who needs to do some actual research and/or present actual science.

I haven't seen anything remotely "scientific" here in the "debunking" of Istvan -- no discussion of the maps showing the detailed underground geology of Caribbean islands, including the aquifers.

Just a general implication that aquifers along coasts are susceptible to salt water intrusion from sea level rise, which may or may not be true in specific cases, depending on the details of the geology.

Without reference to actual data, one can not even be certain where the aquifers are located in specific cases.

Don't forget the sub-sea level lake and salt marshes caught in an accretionary fold down by the DR's southern border with Haiti.

This kerfuffle is reminiscent of how inconvenient issues of isostasy as well as inconveniently high and low islands in the Pacific get lost in the rhetorical shuffle- all sides must go to the Climate Wars with the geography they've got got.

First anon, feel free to jump in with specifics if you like, although you could also take a look at the analogy and link I provided to the issues in southern California.

To emphasize what Eli said, this blog covers a variety of subjects. I've reviewed Game of Thrones here. I'm not a scientist, unlike Eli and John, so I'm the one of us three who's least likely to do traditional science blogging.

Yet, he can determine that because the Supreme Court is going to here arguments on an environmental case case, that four Supreme Court Justices are exercising "...a chance to ruin the global environment."

while Rabett Run does science, it also does policy, communications and on occasion musical interludes.

Fine, so next time in response to a scientific question like "Is an aquifer, on an island or elsewhere, susceptible to salt water influx due to rising seas?", I will expect musical interludes like Four Sea Interludes, by Benjamin Britten?

Ah, but Clownshoe, there's a whole helluva lot more to science than making qualitative statements about what you believe. What you believe is irrelevant to science. What matters is evidence. The evidence states that we are likely to warm the planet 3 degrees or more if we double CO2. It states that we will increase the severity of droughts and flood events. But, hey, work on being able to write English for now. We'll get to how to do science once you can express yourself coherently.

Actually, "1", if you look at the data, it is pretty clear that over periods of decades, the sensitivity is likely to be >3 degrees per doubling. Assuming short equilibrium times tends to underestimate sensitivity. SeeKirk-Davidoff, "On the diagnosis of climate sensitivity using observations of fluctuations."

The top reasons that set Water intrusion LA apart from other companies, is that they consider you to be their top priority and they give their best in unravelling the basis of the problem. The services they provided until now proves of their professionalism and the great work they do. They have made hundreds of houses safe over 25-30 years and still continuing the great job. Their customers are the ones who are promoting their services further because of the quality of work they have experienced with them.

KoFi Button

Subscribe Rabett Run

The Bunny Trail By Email

Contributors

Eli Rabett

Eli Rabett, a not quite failed professorial techno-bunny who finally handed in the keys and retired from his wanna be research university. The students continue to be naive but great people and the administrators continue to vary day-to-day between homicidal and delusional without Eli's help. Eli notices from recent political developments that this behavior is not limited to administrators. His colleagues retain their curious inability to see the holes that they dig for themselves. Prof. Rabett is thankful that they, or at least some of them occasionally heeded his pointing out the implications of the various enthusiasms that rattle around the department and school. Ms. Rabett is thankful that Prof. Rabett occasionally heeds her pointing out that he is nuts.